U.S. patent number 8,182,443 [Application Number 11/654,904] was granted by the patent office on 2012-05-22 for drug administration controller.
This patent grant is currently assigned to MASIMO Corporation. Invention is credited to Massi E. Kiani.
United States Patent |
8,182,443 |
Kiani |
May 22, 2012 |
**Please see images for:
( Certificate of Correction ) ** |
Drug administration controller
Abstract
A drug administration controller has a sensor that generates a
sensor signal to a physiological measurement device, which measures
a physiological parameter in response. A control output responsive
to the physiological parameter or a metric derived from the
physiological parameter causes a drug administration device to
affect the treatment of a person, such as by initiating, pausing,
halting or adjusting the dosage of drugs administered to the
person.
Inventors: |
Kiani; Massi E. (Laguna Niguel,
CA) |
Assignee: |
MASIMO Corporation (Irvine,
CA)
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Family
ID: |
46061215 |
Appl.
No.: |
11/654,904 |
Filed: |
January 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60759673 |
Jan 17, 2006 |
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60764946 |
Feb 2, 2006 |
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Current U.S.
Class: |
604/28; 604/131;
604/66; 604/31; 604/500; 604/65; 604/67; 604/504; 604/503 |
Current CPC
Class: |
A61M
16/12 (20130101); A61M 5/1723 (20130101); A61M
5/142 (20130101); A61M 16/0057 (20130101); A61M
2202/0233 (20130101); A61M 2230/005 (20130101); A61M
2230/10 (20130101); A61M 2230/432 (20130101); A61M
2205/3592 (20130101); A61M 2230/04 (20130101); A61M
2230/30 (20130101); A61M 2230/50 (20130101); A61M
2205/18 (20130101); A61M 2205/502 (20130101); A61M
2230/207 (20130101); A61M 2230/205 (20130101); A61M
2230/42 (20130101); A61M 2205/3561 (20130101); A61M
2230/204 (20130101); A61M 2202/0208 (20130101); A61M
2205/3375 (20130101); A61M 2205/3313 (20130101); A61M
2202/0241 (20130101) |
Current International
Class: |
A61M
1/00 (20060101); A61M 31/00 (20060101); A61M
37/00 (20060101) |
Field of
Search: |
;604/65,131,28,31,66,67,500,503,504 ;600/301 ;128/903 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sirmons; Kevin C
Assistant Examiner: Thomas, Jr.; Bradley
Attorney, Agent or Firm: Knobbe Martens Olson & Bear
LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority benefit under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. No.
60/759,673, filed Jan. 17, 2006, entitled Drug Administration
Controller, and Ser. No. 60/764,946, filed Feb. 2, 2006, entitled
Drug Administration Controller, which are both incorporated by
reference herein.
Claims
What is claimed is:
1. A drug administration method comprising: measuring at least one
physiological parameter with a noninvasive optical sensor attached
to a patient; deriving at least one parameter trend for each
measured physiological parameter, the trend indicating if the at
least one parameter for each measured physiological parameter is
increasing or decreasing at a certain rate over a certain time; and
controlling a drug administration device based at least on one of
the at least one parameter trends, wherein the at least one
physiological parameter includes perfusion index.
2. The drug administration method according to claim 1 further
comprising deriving at least one parameter limit, parameter pattern
and a parameter variability.
3. The drug administration method according to claim 1 wherein
controlling comprises enabling the drug administration device when
perfusion index is trending downward as a marker of pain
stimulus.
4. The drug administration method according to claim 1 wherein
controlling further comprises pausing the drug administration
device when perfusion index is not trending downward.
5. The drug administration method according to claim 1 wherein the
at least one physiological parameter includes HbMet and wherein
controlling comprises pausing the drug administration device when
HbMet is trending upward.
6. The drug administration method according to claim 1 further
comprising deriving a parameter limit and wherein the at least one
physiological parameter includes HbMet and controlling comprises
pausing the drug administration device when HbMet is above HbMet
limit.
7. The drug administration method according to claim 1 comprising
measuring respiration rate with a noninvasive sensor attached to a
patient and deriving a respiration rate trend, wherein controlling
comprises pausing the drug administration device when said RR trend
is trending downward.
8. The drug administration method according to claim 1 comprising
measuring RR with a noninvasive sensor attached to a patient
wherein controlling comprises pausing the drug administration
device when respiration rate is less than a respiration rate
limit.
9. The drug administration method according to claim 1 wherein the
at least one physiological parameter includes HbCO.
10. The drug administration method according to claim 1 comprising
measuring oxygen saturation with a noninvasive sensor attached to a
patient wherein controlling comprises pausing the drug
administration device when a number of cyclical desaturations over
a given timeframe is greater than a predetermined threshold.
11. A drug administration controller comprising: at least one
noninvasive optical sensor that generates at least one sensor
signal in response to a physiological state of a living being; at
least one physiological measurement device that generates
measurements of at least one physiological parameter in response to
the at least one sensor signal, said at least one physiological
parameter including perfusion index; a rules-based processor that
generates a control output in response to at least trends of the
physiological parameter measurements, the trends indicating if the
physiological parameter measurements are increasing or decreasing
at a certain rate over a certain time; and a drug administration
device responsive to one or more control outputs so as to affect
the treatment of the living being including at least one of
initiating, pausing, halting or adjusting the dosage of
administered drugs.
12. The drug administration controller according to claim 11
wherein the drug administration device is one of a drug infusion
device and a medical gas inhalation device.
13. The drug administration controller according to claim 12
wherein the at least one sensor comprises: the optical; and a sound
sensor attached proximate to a neck site so as to measure
respiration rate.
14. The drug administration controller according to claim 11
wherein the at least one blood parameter comprises at least one of
HbMet and HbCO.
Description
BACKGROUND OF THE INVENTION
Physiological measurement systems employed in healthcare often
feature visual and audible alarm mechanisms that alert a caregiver
when a patient's vital signs are outside of predetermined limits.
For example, a pulse oximeter, which measures the oxygen saturation
level of arterial blood, indicates oxygen supply. A typical pulse
oximetry system has a sensor that provides a signal output to a
pulse oximeter monitor. The sensor has an emitter configured with
both red and infrared LEDs that project light through a fleshy
medium to a detector so as to determine the ratio of oxygenated and
deoxygenated hemoglobin light absorption. The monitor has a signal
processor, a display and an alarm. The signal processor inputs the
conditioned and digitized sensor signal and calculates oxygen
saturation (SpO.sub.2) along with pulse rate (PR), as is well-known
in the art. The display provides a numerical readout of a patient's
oxygen saturation and pulse rate. The alarm provides an audible
indication when oxygen saturation or pulse rate are outside of
predetermined limits.
Another pulse oximetry parameter is perfusion index (PI). PI is a
measure of perfusion at the pulse oximetry sensor site comparing
the pulsatile (AC) signal to the non-pulsatile (DC) signal,
expressed as a percentage ratio. An example is the PI Delta
Alarm.TM. feature of the Radical 7.TM. Pulse CO-Oximeter.TM.
available from Masimo Corporation, Irvine, Calif., which alerts
clinicians to specified changes in PI. In particular, PI Delta
indicates if PI at a monitored site decreases by a specific level
(delta) over a specified window of time, with both variables
selectable by the user within predetermined ranges.
Tracking a series of desaturations over time is one metric that is
derived from SpO.sub.2 that is well-known in the art. See, e.g.,
Farney, Robert J., Jensen, Robert L.; Ear Oximetry to Detect Apnea
and Differentiate Rapid Eye Movement (REM) and Non-REM (NREM)
Sleep: Screening for the Sleep Apnea Syndrome; Chest; April 1986;
pages 533-539, incorporated by reference herein. Traditional high
and low SpO.sub.2 alarm limits alert clinicians to saturation
levels that exceed user-selected thresholds, and these thresholds
are typically established at a considerable change from the
patients' baseline saturation level. However, in select patient
populations, substantial desaturation events that exceed a typical
low alarm limit threshold may be preceded by a cycle of transient
desaturations over a limited timeframe. The ability to alert
clinicians to a cycle of these smaller desaturations provides an
earlier indication of a potential significant decline in the
patient's status and the need for more focused monitoring and/or a
change in treatment. An example is the Desat Index Alarm.TM.
feature of the Radical 7.TM., mentioned above, which enables
clinicians to detect an increasing quantity of smaller
desaturations that may precede declining respiratory status. Desat
Index is a measure responsive to patients that experience a
specific number of desaturations beyond a defined level from the
patient's baseline saturation over a specific window of time, with
each of these variables selectable by the user within predetermined
ranges.
A physiological parameter that can be measured in addition to, or
in lieu of, SpO.sub.2 is respiration rate (RR). A respiration rate
monitor utilizes a body sound sensor with piezoelectric membranes
particularly suited for the capture of acoustic waves and the
conversion thereof into electric signals. To detect body sound, the
piezoelectric membranes are used as mechano-electric transducers
that are temporarily polarized when subject to a physical force,
such as when subjected to the mechanical stress caused by the
acoustic waves coming from the inside of a patient's body. The body
sound sensor is typically attached to the suprasternal notch or at
the lateral neck near the pharynx so as to detect tracheal sounds.
A sound sensor is described in U.S. Pat. No. 6,661,161 entitled
Piezoelectric Biological Sound Monitor With Printed Circuit Board,
incorporated by reference herein. A respiration rate monitor is
described in U.S. patent application Ser. No. 11/547,570 entitled
Non-Invasive Monitoring of Respiratory Rate, Heart Rate and Apnea,
incorporated by reference herein.
SUMMARY OF THE INVENTION
Conventional patient monitors give insufficient advance warning of
deteriorating patient health or the onset of a potentially serious
physiological condition. Advantageously, a drug administration
controller is responsive to one or more physiological parameters in
addition to, or in lieu of, SpO.sub.2 and PR, such as
carboxyhemoglobin (HbCO), methemoglobin (HbMet), perfusion index
(PI) and respiration rate (RR), to name a few. Further, a drug
administration controller is advantageously responsive not only to
preset parameter limits but also to various metrics derived from
measured physiological parameters, such as trends, patterns and
variability, alone or in combination, to name a few. As such, a
drug administration controller is adapted to pausing or otherwise
affecting drug administration based upon one or more physiological
parameters and one or more metrics. Parameter variability is
described with respect to PI in U.S. patent application Ser. No.
11/094,813 entitled Physiological Assessment System, incorporated
by reference herein.
As an example, a drug administration controller may be responsive
to changes in HbMet. Gaseous nitric oxide (NO) is increasingly
recognized as an effective bacteriostatic or bacteriocidal agent.
NO, however, can toxically increase HbMet.
A drug administration controller may be responsive to changes in
perfusion index, such as measured by PI Delta, described above. PI
may change dramatically in response to sympathetic changes in
vasoconstriction or vasodilation of peripheral vessels caused by
anesthesia or pain. For example, painful stimulus causes a
significant decline of perfusion index.
As another example, a drug administration controller may be
responsive to a cycle of transient desaturations over a limited
timeframe, such as indicated by Desat Index, described above.
Patients receiving pain medication may be predisposed to
respiratory depression. If the patient has an underlying
respiratory condition, pain medication may cause the patient to
spiral into a cascade of cyclic desaturations, which initially are
mild but may worsen quickly, leading to respiratory depression and
even arrest.
As a further example, a drug administration controller may be
responsive to respiration rate (RR) monitoring, as described above.
RR provides an accurate marker for indicating acute respiratory
dysfunction. For example, during conscious sedation, there is a
risk of respiratory depression, and changes in RR typically provide
an earlier warning than does pulse oximetry alone.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general block diagram of a drug administration
controller;
FIGS. 2A-C are illustrations of drug infusion controller
embodiments;
FIGS. 3A-C are illustrations of medical gas controller
embodiments;
FIG. 4 is a general block diagram of a parameter processor
embodiment; and
FIG. 5 is a detailed block diagram of a parameter processor
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a drug administration controller 100 having one
or more sensors 106 generating sensor signals 107 in response to
physiological states of a living being, such as a patient 1. One or
more physiological measurement devices 108 generate physiological
parameter measurements 103 in response to the sensor signals 107. A
multiple parameter processor 101 processes the parameter
measurements 103 alone or in combination and generates monitor or
control outputs 102, or both, in response. In an open-loop
configuration, one or more monitor outputs 102 are observed by a
caregiver 2, who administers drugs or alters drug doses in
response. Alternatively, or in addition to, the caregiver 2
initiates, pauses, halts or adjusts the settings of a drug
administration device 104. In a closed-loop configuration, a drug
administration device 104 is responsive to one or more control
outputs 102 so as to affect the treatment of the patient 1,
including initiating, pausing, halting or adjusting the dosage of
administered drugs.
As shown in FIG. 1, the drug administration device may be, as
examples, a drug infusion device or a medical gas inhalation
device. Closed loop drug infusion control is described in U.S.
patent application Ser. No. 11/075,389, entitled Physiological
Parameter Controller, incorporated by reference herein. Closed loop
respirator control is described in U.S. Pat. App. No. 60/729,470
entitled Multi-Channel Pulse Oximetry Ventilator Control,
incorporated by reference herein.
Also shown in FIG. 1, sensors 106 may include an optical sensor
attached to a tissue site, such as a fingertip, for measuring one
or more blood parameters. Sensors 106 may also include blood
pressure cuffs, ECG or EEG electrodes, CO.sub.2 measuring
capnography sensors and temperature sensors to name but a few.
Corresponding physiological measurement devices 108 responsive to
these sensors 106 may include blood parameter monitors, blood
pressure monitors, capnometers, ECG and EEG monitors, as a few
examples.
In one embodiment, sensors 106 include a pulse oximetry sensor,
such as described in U.S. Pat. No. 5,782,757 entitled Low Noise
Optical Probes and physiological measurement devices 108 include a
pulse oximeter, such as described in U.S. Pat. No. 5,632,272
entitled Signal Processing Apparatus, both assigned to Masimo
Corporation, Irvine, Calif. and both incorporated by reference
herein. In another embodiment, sensors 106 and measurement devices
108 include a multiple wavelength sensor and a corresponding
noninvasive blood parameter monitor, such as the RAD-57.TM. and
Radical-7.TM. for measuring SpO.sub.2, CO, HbMet, pulse rate,
perfusion index and signal quality. The RAD-57 and Radical-7 are
available from Masimo Corporation, Irvine, Calif. In other
embodiments, sensors 106 also include any of LNOP.RTM. adhesive or
reusable sensors, SofTouch.TM. sensors, Hi-Fi Trauma.TM. or
Blue.TM. sensor all available from Masimo Corporation, Irvine,
Calif. Further, measurement devices 108 also include any of
Radical.RTM., SatShare.TM., Rad-9.TM., Rad-5.TM., Rad-5v.TM. or
PPO+.TM. Masimo SET.RTM. pulse oximeters all available from Masimo
Corporation, Irvine, Calif.
In a particular embodiment, the control or monitor outputs 102 or
both are responsive to a Desat Index or a PI Delta or both, as
described above. In another particular embodiment, one or more of
the measurement devices 108, the parameter processor 101 and the
drug administrative device 104 are incorporated within a single
unit. For example, the devices may be incorporated within a single
housing, or the devices may be separately housed but physically and
proximately connected.
Although sensors 106 are described above with respect to
noninvasive technologies, sensors 106 may be invasive or
noninvasive. Invasive measurements may require a person to prepare
a blood or tissue sample, which is then processed by a
physiological measurement device.
FIG. 2A illustrates a drug infusion controller embodiment 200
comprising a drug-infusion pump 204, an optical sensor 206 attached
to a patient 1 and a noninvasive blood parameter monitor 208. The
optical sensor 206 provides a sensor signal via a sensor cable 207
to the blood parameter monitor 208. The blood parameter monitor 208
generates blood parameter measurements and processes those
parameters to generate monitor and control outputs 203 (FIG. 1), as
described in further detail with respect to FIGS. 4-5, below. In
particular, the blood parameter monitor 208 generates control
signals via a control cable 202 to the drug-infusion pump 204, and
the drug-infusion pump 204 administers drugs to the patient 1 via
an IV 209, accordingly.
In one embodiment, the administered drug is a nitrate, such as
sodium nitroprusside, and the blood parameter monitored is HbMet.
In a particular embodiment, the blood parameter monitor 208
provides a control output according to one or more entries in TABLE
1. In another particular embodiment, the blood parameter monitor
208 provides a control output according to one or more entries in
TABLE 2. In yet another embodiment, a blood parameter monitor 208
confirms that the measurement of HbMet is accurate, such as by
checking a signal quality parameter or by having multiple sensors
206 on the patient 1.
FIG. 2B illustrates another drug infusion controller embodiment 201
comprising an optical sensor 206 and a combination blood-parameter
monitor/drug-infusion pump 205. In an embodiment, the drug infusion
controller 200, 201 provides a visual display or audible alarm
indicating various degrees of patient condition, such as green,
yellow and red indicators or intermittent and low volume, medium
volume and high volume tones.
TABLE-US-00001 TABLE 1 Rule-Based Monitor Outputs RULE OUTPUT If
HbMet > limit threshold disable pump; trigger alarm If HbMet
trend > trend threshold disable pump; trigger alarm
TABLE-US-00002 TABLE 2 Rule-Based Monitor Outputs RULE OUTPUT If
HbMet > limit threshold disable pump; trigger alarm If HbMet
trend > trend threshold reduce dosage; activate caution
indicator
Another embodiment involves patient controlled analgesia (PCA),
i.e. the administered drug is an analgesia, and administration of
the drug is controlled by the patient according to perceived pain
levels. Analgesia administration, however, is paused in response to
one or more blood parameters and corresponding metrics. In one
embodiment, the blood parameter monitored is SpO.sub.2 and the
blood parameter monitor 208 provides a control output responsive to
Desat Index. In a particular embodiment, PCA is paused or disabled
according to TABLE 3.
TABLE-US-00003 TABLE 3 Rule-Based PCA Control Outputs RULE OUTPUT
If Desat Index > index limit pause PCA for predetermined period;
activate alarm
In another embodiment, the blood parameter monitor 208 provides a
control output responsive to a PI indication of pain. In this
manner, the administration of anesthesia is controlled according to
the patient's perceived pain level. In a particular embodiment, PCA
is paused or enabled according to one or more entries of TABLE 4,
where a falling PI results in a negative PI Delta relative to an
established baseline.
TABLE-US-00004 TABLE 4 Rule-Based PCA Control Outputs RULE OUTPUT
If PI Delta < delta limit enable PCA; activate caution indicator
If PI Delta > delta limit disable PCA
FIG. 2C illustrates yet another drug infusion controller embodiment
211 having a piezoelectric sensor 216 and a combination
blood-parameter/piezoelectric sound monitor/drug infusion pump 218.
A piezoelectric sensor 216 is attached to a patient's body 1 so as
to detect tracheal sounds. The corresponding sensor signal is
transmitted to the sound monitor 218 via a sensor cable 217. The
sound monitor/pump 218 generates biological sound measurements such
as respiration rate (RR) and processes the measurements to generate
control outputs. In a particular embodiment, the monitor/pump 218
provides a control output according to one or more entries of TABLE
5.
TABLE-US-00005 TABLE 5 Rule-Based Monitor Outputs RULE OUTPUT If RR
trend < trend threshold reduce dosage; activate caution
indicator If RR < limit threshold disable pump; trigger
alarm
FIG. 3A illustrates a medical gas controller embodiment 300
comprising a ventilator 304 adapted to supply both oxygen and a
medical gas, an optical sensor 306 attached to a patient 1, and a
noninvasive blood parameter monitor 308. The optical sensor 306
provides a sensor signal via a sensor cable 307 to the blood
parameter monitor 308. The blood parameter monitor 308 generates
blood parameter measurements and processes those parameters to
generate monitor and control outputs, as described with respect to
FIGS. 4-5, below. In particular, the blood parameter monitor 308
generates control signals via a control cable 302 to the ventilator
304, and the ventilator 304 administers a medical gas to the
patient 1 via a breathing apparatus 309 accordingly. FIG. 3B
illustrates another medical gas controller embodiment 301
comprising an optical sensor 306 and a combination blood-parameter
monitor/ventilator 305.
In one embodiment, the administered medical gas is a NO, and the
blood parameter monitored is HbMet. In a particular embodiment, the
blood parameter monitor 308 provides a control output according to
one or more entries of TABLE 6. In another particular embodiment,
the blood parameter monitor 308 provides a control output according
to one or more entries of TABLE 7. In yet another embodiment, a
blood parameter monitor 308 confirms that the measurement of HbMet
is accurate, such as by checking a signal quality parameter or by
having multiple sensors 306 on the patient 1. In a further
embodiment, the administered medical gas is CO, and the blood
parameter monitored is HbCO.
TABLE-US-00006 TABLE 6 Rule-Based Monitor Outputs RULE OUTPUT If
HbMet trend > trend threshold halt NO flow; trigger alarm If
HbMet > limit threshold halt NO flow; trigger alarm
TABLE-US-00007 TABLE 7 Rule-Based Monitor Outputs RULE OUTPUT If
HbMet trend > trend threshold reduce NO flow; activate caution
indicator If HbMet > limit threshold halt NO flow; trigger
alarm
FIG. 3C illustrates yet another medical gas controller embodiment
311 comprising a piezoelectric sound sensor 316 and a combination
blood-parameter/piezoelectric sound monitor/ventilator 315. The
sound sensor 316 is attached to a patient's body 1 so as to detect
tracheal sounds and provides a sensor signal via a sensor cable 317
to the sound monitor 315. The sound monitor/ventilator 315
generates biological sound measurements such as respiration rate
(RR) and provides control outputs responsive to RR. In a particular
embodiment, the monitor/ventilator 315 provides a control output
according to one or more entries of TABLE 8.
TABLE-US-00008 TABLE 8 Rule-Based Monitor Outputs RULE OUTPUT If RR
trend < trend threshold reduce medical gas flow; activate
caution indicator If RR limit < limit threshold halt medical gas
flow; trigger alarm
FIG. 4 illustrates a parameter processor 101, which may comprise an
expert system, a neural-network or a logic circuit as examples. The
parameter processor 101 has as inputs 103 one or more parameters
from one or more physiological measurement devices 108 (FIG. 1).
Noninvasive parameters may include oxygen saturation (SpO.sub.2),
pulse rate, perfusion index, HbCO, HbMet and other Hb species, and
data confidence indicators, such as derived from a pulse oximeter
or a Pulse Co-Oximeter.TM. (Masimo Corporation) to name a few.
Invasive parameters may include lactate, glucose or other blood
constituent measurements. Capnography parameters may include, for
example, end tidal carbon dioxide (ETCO.sub.2) and respiration
rate. Other measurement parameters that can be input to the
parameter processor 101 may include ECG, EEG, blood pressure and
temperature to name a few. All of these parameters may indicate
real-time measurements or historical data, such as would indicate a
measurement trend. Pulse oximetry signal quality and data
confidence indicators are described in U.S. Pat. No. 6,684,090
entitled Pulse Oximetry Data Confidence Indicator, assigned to
Masimo Corporation, Irvine, Calif. and incorporated by reference
herein.
As shown in FIG. 4, monitor outputs 102 may be alarms, wellness
indicators, controls and diagnostics. Alarms may be used to alert
medical personnel to a potential urgent or emergency medical
condition in a patient under their care. Wellness indicators may be
used to inform medical personnel as to patient condition stability
or instability, such as a less urgent but potentially deteriorating
medical state or condition. Controls may be used to affect the
operation of a medical treatment device or other medical-related
equipment. Diagnostics may be messages or other indicators used to
assist medical personnel in diagnosing or treating a patient
condition.
User I/O 60, external devices 70 and wireless communication 80 also
interface with the parameter processor 101 and provide
communications to the outside world. User I/O 60 allows manual data
entry and control. For example, a menu-driven operator display may
be provided to allow entry of predetermined alarm thresholds.
External devices 70 may include PCs and network interfaces to name
a few.
FIG. 5 illustrates one embodiment of a parameter processor 101
having a pre-processor 510, a metric analyzer 520, a post-processor
530 and a controller 540. The pre-processor 510 has inputs 103 that
may be real-time physiological parameter measurements, historical
physiological parameter measurements, signal quality measures or
any combination of the above. The pre-processor 510 generates
metrics 512 that may include historical or real-time parameter
trends, detected parameter patterns, parameter variability measures
and signal quality indicators to name a few. As examples, trend
metrics may indicate if a physiological parameter is increasing or
decreasing at a certain rate over a certain time, pattern metrics
may indicate if a parameter oscillates within a particular
frequency range or over a particular time period, variability
metrics may indicate the extent of parameter stability.
As shown in FIG. 5, the metric analyzer 520 is configured to
provide test results 522 to the post-processor based upon various
rules applied to the metrics 512 in view of various thresholds 524.
As an example, the metric analyzer 520 may output an alarm trigger
522 to the post-processor 530 when a parameter measurement 103
increases faster than a predetermined rate. This may be expressed
by a rule that states "if trend metric exceeds trend threshold then
trigger alarm."
Also shown in FIG. 5, the post processor 530 inputs test results
522 and generates outputs 102 including alarms, wellness indictors,
controls and diagnostics. Alarms may be, for example, audible or
visual alerts warning of critical conditions that need immediate
attention. Wellness indicators may be audible or visual cues, such
as an intermittent, low-volume tone or a red/yellow/green light
indicating a patient with a stable or unstable physiological
condition. Controls may be electrical or electronic, wired or
wireless or mechanical outputs, to name a few, capable of
interfacing with and affecting another device. As examples,
controls 102 may interface with drug-infusion equipment or medical
gas ventilation equipment, as described with respect to FIGS. 2A-C
and 3A-C, above.
Further shown in FIG. 5, the controller 540 interfaces with I/O
109, as described with respect to FIG. 4, above. In one embodiment,
the I/O 109 provides predetermined thresholds, which the controller
540 transmits to the metric analyzer 520. The controller 540 may
also define metrics 514 for the pre-processor 510 and define
outputs 534 for the post-processor 530.
A drug administration controller has been disclosed in detail in
connection with various embodiments. These embodiments are
disclosed by way of examples only and are not to limit the scope of
the claims that follow. One of ordinary skill in art will
appreciate many variations and modifications.
* * * * *